Create Action server

#ros2   #python   #action  

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Table of Content

VSCode action intellisense

Add path to search to python.analysis.extraPaths list in settings.json

{
"python.analysis.extraPaths": [
    "/home/user/ros2_ws/install/action_tutorial_interfaces/local/lib/python3.10/dist-packages"
    ]
}

demo

action_tutorial/my_server.py

import rclpy
from rclpy.action import ActionServer
from rclpy.node import Node
from rclpy.action.server import ServerGoalHandle
from action_tutorial_interfaces.action import MyAction

TOPIC = "my_action_demo"

class MyActionServer(Node):
    def __init__(self):
        super().__init__('my_action_server')
        self._action_server = ActionServer(
            self,
            MyAction,
            TOPIC,
            self.execute_callback)
        self.get_logger().info('Start my_action_server version')

    def execute_callback(self, goal_handle: ServerGoalHandle):
        feedback_msg = MyAction.Feedback()
        for i in range(goal_handle.request.count):
            self.get_logger().info('current: {}'.format(i))
            feedback_msg.current = i
            goal_handle.publish_feedback(feedback_msg)

        self.get_logger().info('Action ended')
        goal_handle.succeed()

        result = MyAction.Result()
        result.total = i
        return result


def main(args=None):
    rclpy.init(args=args)
    action_server = MyActionServer()
    rclpy.spin(action_server)

if __name__ == '__main__':
    main()

Test

send_goal

ros2 action send_goal -f /my_action_demo action_tutorial_interfaces/action/MyAction "{count: 5}"
Waiting for an action server to become available...
Sending goal:
     count: 5

Goal accepted with ID: c1129edf0f894012921b849b7948703a

Feedback:
    current: 0

Feedback:
    current: 1

Feedback:
    current: 2

Feedback:
    current: 3

Feedback:
    current: 4

Result:
    total: 4

Goal finished with status: SUCCEEDED